Edexcel GCSE Combined Science key terms

A rock containing enough metal or metal compound to make extracting the metal economically worthwhile.

A structure inside a cell that performs a particular function, such as a mitochondrion or chloroplast.

A single living thing.

The net movement of water through a partially permeable membrane from a more dilute solution to a more concentrated solution.

An electron in the outermost occupied shell of an atom.

A result that is markedly different from the other results obtained under the same conditions.

The release of a mature egg from an ovary.

The loss of electrons by a substance in a reaction.

Compounds of nitrogen and oxygen, such as NO and NO₂, formed when nitrogen and oxygen react at high temperatures.

Describes a substance that can support combustion, for example by providing oxygen, and make a fire more intense.

A technique that separates soluble substances in a mixture because they move at different rates as a solvent travels through paper.

A circuit with separate branches connected between the same two points, providing more than one path for current.

An organism that lives in or on a host and obtains resources from it, harming the host.

A relationship between species in which a parasite benefits by obtaining resources from a host, which is harmed.

The nucleus that undergoes radioactive decay.

A barrier that allows some substances to pass through but prevents others from passing through.

A model that represents matter as particles and explains its properties through their arrangement, movement and interactions.

A disease-causing microorganism.

Evaluation of research by other scientists before it is published.

The ability of radiation to pass through a material.

The percentage of a compound’s total mass contributed by a particular element.

A value below which a stated percentage of a reference population falls. For example, the 25th percentile for mass is the mass below which approximately 25% of the comparison group falls.

The effectiveness of a contraceptive method when it is used correctly every time.

The time taken for one complete oscillation, or for one complete wave to pass a point, measured in seconds (s).

A table arranging elements so that patterns in their properties can be recognised. The modern table is ordered by increasing atomic number.

A magnet that retains its magnetism and produces its own magnetic field without needing an external magnetic field.

A large compartment in a plant cell containing cell sap and helping to keep the cell firm.